Black Jasper with Quartz Veining
Silicon Dioxide (Microcrystalline Quartz) var. Jasper · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal; typically occurs in massive, microcrystalline (cryptocrystalline) habits with no visible external crystal faces.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (predominantly) with impurities of iron oxides and carbonaceous matter
Formation Process
Primarily sedimentary or hydrothermal; forms as silica-rich fluids permeate porous rocks or volcanic ash, slowly precipitating microcrystalline quartz.
About This Crystal
An opaque, deep black to dark charcoal-grey jasper polished into a heart shape. It features prominent white to light grey linear veining caused by secondary quartz infiltration into fractures.
Physical Characteristics
Color: Black with white veins; Streak: White; Cleavage: None; Fracture: Conchoidal to uneven; Specific Gravity: 2.58–2.91; Luster: Vitreous to waxy when polished.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009 (usually not measurable in opaque masses); Pleochroism: None; Optical Character: Uniaxial positive.
Hardness & Durability
Origin Region
Found globally; notable sources for black jasper include India, Brazil, Australia, and the United States (California/Oregon).
Hardness & Durability
Mohs Hardness: 6.5–7; Toughness: Excellent due to its microcrystalline structure; Stability: High, resistant to light and most chemicals.
Care & Maintenance
Safe to clean with warm soapy water and soft brushes. Avoid harsh ultrasonic cleaners if fractures in veining are deep; store separately to prevent scratching softer stones.
Rarity & Value
Common; relatively inexpensive. Value is determined by the aesthetic pattern of the veining and the quality of the polish; typically a few dollars for small carved specimens.
Special Characteristics
Displays 'veined' or 'brecciated' appearance where white quartz has healed cracks in the primary black jasper matrix.
Lore & History
Historically used as a 'touchstone' to test the purity of gold and silver. Metaphysically associated with the Root Chakra, grounding, protection, and providing stability during times of change.